Thomas hookeb



T. HOOKER.

MIGROMETER.

(No Model.)

No h 97,602.

Patented Apr. 29

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UNTTED STATES PATENT ,FFICEQ THOMAS OF SYRACUSE, NEW YORK.

MICROMETER.

SPECIFICATION forming part of Letters Patent No. 297,602, dated April 29, 1884.

Application filed March 2l, 1883. (No model.) I i Syracuse, Onondaga county, New York, a citizen of the United States, have invented a new and Improved Micrometer, of which the following is a specification, reference being had to the accompanying drawings, in which- Figure l'is a side elevation with a portion of the body or case broken out to showthe interior mechanism Fig. 2, an end view; Fig. 3, a side view of a modification; Fig. 4, a front view of Fig. 3, showing the graduated scale; Fig. 5, an enlarged view of the sliding bar in Fig. 3. Fig. 6 shows it mounted for use as a surface-gage.

The object of my invention is to provide a micrometer which will both indicate and accurately measure slight differences of size between articles or portions of the same article upon comparing them one with another or with a standard gage.

It consists, first, of a-body inclosing a slidingbar and carrying an index-needle actuated by the sliding bar, with a graduated scale upon the end of the body and an adjustingscrew opposite to the sliding bar, the screw and bar forming the jaws; second, of a multiplyin g index-needle actuated directly by the sliding bar without the aid or intervention of lever-bars; third, of a micrometer provided with a scale graduated both ways from a central zero-point at the extremity of the indexneedle; fourth, of an index-needle and sliding bar operating together and both controlled by a spring acting directly upon the index-needle and through it upon the sliding bar in the head of the micrometer; fifth, of the several combinations of parts hereinafter specified.

It is constructed as follows: A is the body of the micrometer, consisting of a shell, body, or case of suitable shape to inclo'se or carry an index-needle. I11 Fig. 1 it forms a rectangular box, upon which the arm .15 slides and is clamped and adjusted.

B is the head containing the sliding bar 0 with the handle 0 upon its outer end. Upon the upper sideof this bar 0 is a projecting stud, d. l

or ring, by which the bar may be drawn back to aidinintroducing the article to be measured. The sliding arm Eis clamped upon the body The handle 0 maybe either a knob in any desired position by means of the cam- ,lever F in Fig. 1. In the lower end of this arm I insert the adjusting-screw H thr igh a split nut, h, and regulate it by the clamping screw i.

D is a scale for measuring the variations. It is graduated both ways from a central zeropoint in such a manner and proportion that each division measures a definite amount of motion in the sliding bar-as, for instance, one-thonsandth of an inch but it is shown upon an enlarged scale, so as to be more easily read.

I is the index-needle, mounted upon the pivot Z. Upon its lower end is ashoulder,m, which engages with the stud (1 upon the sliding bar 0. The outer end of the needle extends to the scale D. The pivot Z is also the fulcral bearing of the index-needle. The travel of the sliding bar is multiplied to any desired proportion upon the scale D by varying the length of the needle-arm below the pivotl and the relative proportion of such length to that of the needle above the pivot.

Lis a spring inclosed in and with one end secured to the body A. The other end bears against the edge,of the needle I. This spring acts directly upon the needle I, and --through it, by the shoulder m and stud d, upon the sliding bar 0 and regulates the movement of both so as to throw them both back to their normal position.

The body A is provided, usually, with a removable cover, a, held in place by screws b. A gib, f, can be used between thecam of the lever F and the body A to take the wear and protect the body.

b b are stops, which may be used to limitthe movement of the needle.

It is operated as follows: To ascertainwhether an article is of a certain size, a standard gage of that size is placed between the sliding bar 0 and screw H, the arm E being moved to the proper position and clamped. The screw H is then turned until the pressure upon the gage, transmitted through it to the bar 0- and through that to the needle-arm, slides the bar 0 outward until the point of the needle I is brought to the zero-point on the scale D. The screw H is then set by the screw t, and the gage is then removed. The article to be measured is now introduced between the screw H and bar 0, the bar being drawn back by the handle 0, if desired, to facilitate the introduction. Then a glance at the scale D shows by the position of the needlepoint just how much the article varies from the gage, either larger or smaller. If the article be larger, then the needle-point will in Fig. 1 be below the zero, and if smaller above it.

In Figs. 3 and 4 are shown modifications of the form of construction, embodying the same principle of operation. In this form of construction the arm E is bent at right angles, and passes through the clamp O on the edge of the body A, and is held by the screw F. The spline f, fitting in a seat in the arm E, prevents the body A from twisting upon the arm. The body is fan-shaped to give greater play td thc needle. The needle is pivoted the same as in Fig. 1. The same form of sliding bar C may be used or that shown in Fig. 6, in which, in place of the stud d, a spiral rib or slot, 8, is shown to engage with the shoulder in on the needle. This style of bar should also have a spline, t, upon it to prevent its revolving and cause it to slide in a straight line. Motion is imparted to the needle by the spiral s on the sliding bolt 0 by its contact with the shoulder in. In this construction the needle I is straight. The spring L operates in the same way as in Fig. 1., and the scale D is graduated in the same manner. The screw H is mounted and operates the same as in Fig. 1.

The horizontal portion of the bar E in Fig. 3 may be fastened to the body A, either parallel with or at right angles to the plane of motion of the needle; and the scale may be attached to the needle and move with it, and act either as a direct measure or as a Vernier.

By reversing the bar 0 and screw H, the instrument can be used for internal measurements. 1

Fig. 7 shows a form of construction adapting it to use as a surface-gage by means of the standard-arm E, adj usti n g-arms c c, and clamp ing-screws n o 1). As a surface-gage, the meas urements are taken from the platen of the machine upon which the article lies, the standard E being set upon the platen and the bar 0 moved around over the surface of the article. The arrangement of the sliding bolt 0 and its projecting at either end from the head not only adapts it to serve as a jaw, but at its opposite end as a handle to be positively operated in opening the micrometer for application to pieces to be gaged.

Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. In a micrometer, a jaw connected to the needle and consisting of a sliding bar projecting at both ends from the head, substantially as specified.

2. In a micrometer, a jaw consisting of a sliding bar provided with a stud operating in a slot in the index-needle, and with a handle or end projecting from the head, substantially as specified.

3. In a micrometer, a jaw consisting of a sliding bar arranged at a right angle to the index-needle and provided with a spiral stud, substantially as specified.

4. The arm E, carrying the adjusting-nut H and set-screw i, in combination with a body, A, carrying an index-needle, I, and a projecting sliding bar 0, having a rib, (Z, and handle 0, substantially as shown and described.

5. The combination. of the body A, carrying the needle I, spring L, and sliding projecting rod 0, these elements constituting one portion of a micrometer, with the arm E, carrying the adjusting-screw H and set-screw i, constituting the remaining portion, and with means, substantially as shown and described, for adjustably securing one of said portions to the other, substantially as and for the purposes set forth.

6. The combination of the head B, sliding bar 0, projecting at each end therefrom and having a stud, the slotted needle I, and the spring L, whereby the jaw may be opened and the needle operated from the outside of the head, and the jaw automatically self-closed against an object to be gaged.

7. In a micrometer, a jointless index-needle and sliding bar operating. together, and both controlled by a spring acting directly upon the needle, and through that upon the slidingbar, constructed and operating together substantially as set forth.

S. In a micrometer, the combination of the needle I, sliding bar C, projecting at both ends, spring L, scale D, arm E, and screw II, with the body A, constructed and operating together substantially as and for the purposes set forth.

9. In a micrometer, a sliding bar, 0, provided with a handle, 0, a multiplying-needle, I, and spring L, acting directly upon the scale D, in combination with the arm E and screw II, constructed and operating together substantially as described, for the purposes specified.

10. A micrometer consisting of the bar 0, needle I, and spring L, inclosed in the body A, a scale, D, upon the body, and a screw, I-I, inclosed in the arm E, in combination with each other and operating together substantially as and for the purposes set forth.

In witness whereof I have hereunto set my hand this 27th day of February, 1883.

THOMAS HOOKER.

In presence of 0. WV. SMITH, WILLIAM E. Frron'. 

